行為變更：所有應用程式

Android 15 平台包含可能對應用程式造成影響的行為變更。無論 targetSdkVersion 為何，當應用程式在 Android 15 上執行時，下列行為變更將會套用至所有應用程式。您應測試應用程式，並視需要修改，以便在適當情況下支援新版本功能。

另請務必查看僅對指定 Android 15 為目標版本的應用程式造成影響的行為變更。

核心功能

Android 15 修改或擴充了 Android 系統的各種核心功能。

套件停止狀態的變更

The intention of the package FLAG_STOPPED state (which users can engage in AOSP builds by long-pressing an app icon and selecting "Force Stop") has always been to keep apps in this state until the user explicitly removes the app from this state by directly launching the app or indirectly interacting with the app (through the sharesheet or a widget, selecting the app as live wallpaper, etc.). In Android 15, we've updated the behavior of the system to be aligned with this intended behavior. Apps should only be removed from the stopped state through direct or indirect user action.

To support the intended behavior, in addition to the existing restrictions, the system also cancels all pending intents when the app enters the stopped state on a device running Android 15. When the user's actions remove the app from the stopped state, the ACTION_BOOT_COMPLETED broadcast is delivered to the app providing an opportunity to re-register any pending intents.

You can call the new ApplicationStartInfo.wasForceStopped() method to confirm whether the app was put into the stopped state.

支援 16 KB 頁面大小

過去 Android 僅支援 4 KB 的記憶體分頁大小，這已針對 Android 裝置通常擁有的平均總記憶體量，最佳化系統記憶體效能。從 Android 15 開始，AOSP 支援設定為使用 16 KB 頁面大小的裝置 (16 KB 裝置)。如果應用程式使用任何 NDK 程式庫 (直接或透過 SDK 間接使用)，您必須重建應用程式，才能在這些 16 KB 裝置上運作。

隨著裝置製造商持續打造實體記憶體 (RAM) 容量更大的裝置，許多裝置將採用 16 KB (最終會更大) 的分頁大小，以最佳化裝置效能。為 16 KB 頁面大小的裝置新增支援功能，可讓應用程式在這些裝置上執行，並享有相關的效能提升優勢。如果沒有重新編譯，應用程式就無法在日後的 Android 版本中，於 16 KB 裝置上運作。

為協助您為應用程式新增支援功能，我們提供了相關指南，說明如何檢查應用程式是否受到影響、如何重建應用程式 (如適用)，以及如何使用模擬器 (包括 Android Emulator 的 Android 15 系統映像檔)，在 16 KB 環境中測試應用程式。

Benefits and performance gains

以 16 KB 頁面大小設定的裝置平均會耗用較多記憶體，但系統和應用程式也能獲得各種效能改善：

  • 系統面臨記憶體壓力時，應用程式啟動時間越短：平均低 3.16%，部分受測的應用程式還大幅改善 (最多提升 30%)
  • 應用程式啟動期間的耗電量降幅：平均減少 4.56%
  • 相機啟動速度更快：熱啟動速度平均快了 4.48%，冷啟動速度平均快了 6.60%
  • 縮短系統啟動時間：縮短 8% (平均約 950 毫秒)

這些改善項目是根據初步測試結果而來，實際裝置上的結果可能會有所不同。我們會在持續測試的過程中，針對應用程式可能獲得的效益提供額外分析。

Check if your app is impacted

如果應用程式使用任何原生程式碼，請重新建構應用程式，支援 16 KB 裝置。如果您不確定應用程式是否使用原生程式碼，可以使用 APK 分析工具找出是否有任何原生程式碼，然後檢查找到的任何共用程式庫的 ELF 區段是否對齊。Android Studio 也提供相關功能，可協助您自動偵測對齊問題。

如果應用程式只使用以 Java 程式設計語言或 Kotlin 編寫的程式碼 (包括所有程式庫或 SDK)，則應用程式已可支援 16 KB 裝置。不過，我們建議您在 16 KB 環境中測試應用程式，確認應用程式行為沒有發生非預期的迴歸。

部分應用程式支援私人空間的必要變更

Private space is a new feature in Android 15 that lets users create a separate space on their device where they can keep sensitive apps away from prying eyes, under an additional layer of authentication. Because apps in the private space have restricted visibility, some types of apps need to take additional steps to be able to see and interact with apps in a user's private space.

All apps

Because apps in the private space are kept in a separate user profile, similar to work profiles, apps shouldn't assume that any installed copies of their app that aren't in the main profile are in the work profile. If your app has logic related to work profile apps that make this assumption, you'll need to adjust this logic.

Medical apps

When a user locks the private space, all apps in the private space are stopped, and those apps can't perform foreground or background activities, including showing notifications. This behavior might critically impact the use and function of medical apps installed in the private space.

The private space setup experience warns users that the private space is not suitable for apps that need to perform critical foreground or background activities, such as showing notifications from medical apps. However, apps can't determine whether or not they're being used in the private space, so they can't show a warning to the user for this case.

For these reasons, if you develop a medical app, review how this feature might impact your app and take appropriate actions—such as informing your users not to install your app in the private space—to avoid disrupting critical app capabilities.

Launcher apps

If you develop a launcher app, you must do the following before apps in the private space will be visible:

  1. Your app must be assigned as the default launcher app for the device—that is, possessing the ROLE_HOME role.
  2. Your app must declare the ACCESS_HIDDEN_PROFILES normal permission in your app's manifest file.

Launcher apps that declare the ACCESS_HIDDEN_PROFILES permission must handle the following private space use cases:

  1. Your app must have a separate launcher container for apps installed in the private space. Use the getLauncherUserInfo() method to determine which type of user profile is being handled.
  2. The user must be able to hide and show the private space container.
  3. The user must be able to lock and unlock the private space container. Use the requestQuietModeEnabled() method to lock (by passing true) or unlock (by passing false) the private space.

  4. While locked, no apps in the private space container should be visible or discoverable through mechanisms such as search. Your app should register a receiver for the ACTION_PROFILE_AVAILABLE and ACTION_PROFILE_UNAVAILABLE broadcasts and update the UI in your app when the locked or unlocked state of the private space container changes. Both of these broadcasts include EXTRA_USER, which your app can use to refer to the private profile user.

    You can also use the isQuietModeEnabled() method to check whether the private space profile is locked or not.

App store apps

The private space includes an "Install Apps" button that launches an implicit intent to install apps into the user's private space. In order for your app to receive this implicit intent, declare an <intent-filter> in your app's manifest file with a <category> of CATEGORY_APP_MARKET.

移除以 PNG 為基礎的表情符號字型

The legacy, PNG-based emoji font file (NotoColorEmojiLegacy.ttf) has been removed, leaving just the vector-based file. Beginning with Android 13 (API level 33), the emoji font file used by the system emoji renderer changed from a PNG-based file to a vector based file. The system retained the legacy font file in Android 13 and 14 for compatibility reasons, so that apps with their own font renderers could continue to use the legacy font file until they were able to upgrade.

To check if your app is affected, search your app's code for references to the NotoColorEmojiLegacy.ttf file.

You can choose to adapt your app in a number of ways:

  • Use platform APIs for text rendering. You can render text to a bitmap-backed Canvas and use that to get a raw image if necessary.
  • Add COLRv1 font support to your app. The FreeType open source library supports COLRv1 in version 2.13.0 and higher.
  • As a last resort, you can bundle the legacy emoji font file (NotoColorEmoji.ttf) into your APK, although in that case your app will be missing the latest emoji updates. For more information, see the Noto Emoji GitHub project page.

最低目標 SDK 版本從 23 提高至 24

Android 15 採用 Android 14 所做的變更，並將這項做法 在 Android 15 中， 24 以下版本的 targetSdkVersion 無法安裝。 要求應用程式符合現代 API 級別，有助於提供更完善的安全防護和 隱私權。

為了規避 Android 較新版本的安全性和隱私權保護措施，惡意軟體通常會鎖定較低的 API 級別。例如： 部分惡意軟體應用程式會使用 22 的 targetSdkVersion，以免受到 Android 6.0 Marshmallow (API) 在 2015 年推出的執行階段權限模型 第 23 級)。這項 Android 15 變更會讓惡意軟體更難躲過更嚴謹的安全性和隱私權措施。嘗試安裝以較低 API 為目標的應用程式 level 會導致安裝失敗，並顯示以下訊息： 出現在 Logcat 中：

INSTALL_FAILED_DEPRECATED_SDK_VERSION: App package must target at least SDK version 24, but found 7

在升級至 Android 15 的裝置上，targetSdkVersion 較低的所有應用程式 仍未解除安裝。

如要測試以舊版 API 級別為目標的應用程式，請使用下列 ADB 指令：

adb install --bypass-low-target-sdk-block FILENAME.apk

安全性和隱私權

Android 15 introduces robust measures to combat one-time passcode (OTP) fraud and to protect the user's sensitive content, focusing on hardening the Notification Listener Service and screenshare protections. Key enhancements include redacting OTPs from notifications accessible to untrusted apps, hiding notifications during screenshare, and securing app activities when OTPs are posted. These changes aim to keep the user's sensitive content safe from unauthorized actors.

Developers need to be aware of the following to ensure their apps are compatible with the changes in Android 15:

OTP Redaction

Android will stop untrusted apps that implement a NotificationListenerService from reading unredacted content from notifications where an OTP has been detected. Trusted apps such as companion device manager associations are exempt from these restrictions.

Screenshare Protection

  • Notification content is hidden during screen sharing sessions to preserve the user's privacy. If the app implements setPublicVersion(), Android shows the public version of the notification which serves as a replacement notification in insecure contexts. Otherwise, the notification content is redacted without any further context.
  • Sensitive content like password input is hidden from remote viewers to prevent revealing the user's sensitive information.
  • Activities from apps that post notifications during screenshare where an OTP has been detected will be hidden. App content is hidden from the remote viewer when launched.
  • Beyond Android's automatic identification of sensitive fields, developers can manually mark parts of their app as sensitive using setContentSensitivity, which is hidden from remote viewers during screenshare.
  • Developers can choose to toggle the Disable screen share protections option under Developer Options to be exempted from the screenshare protections for demo or testing purposes. The default system screen recorder is exempted from these changes, since the recordings remain on-device.

相機和媒體

Android 15 會對所有應用程式的相機和媒體行為進行下列變更。

達到資源限制時，直接和卸載音訊播放會使先前開啟的直接或卸載音軌失效

在 Android 15 之前，如果應用程式在其他應用程式播放音訊時要求直接或卸載音訊播放，且已達到資源限制，應用程式就會無法開啟新的 AudioTrack。

自 Android 15 起，當應用程式要求直接或卸載播放功能，且已達到資源限制時，系統會使任何目前開啟的 AudioTrack 物件失效，以免無法滿足新曲目要求。

(直接和卸載音訊音軌通常會在播放壓縮音訊格式時開啟。直接播放音訊的常見用途包括透過 HDMI 將編碼音訊串流至電視。卸載音軌通常用於在行動裝置上播放經過壓縮的音訊，並使用硬體 DSP 加速功能。

使用者體驗和系統 UI

Android 15 包含一些變更，旨在打造更一致、直覺的使用者體驗。

為已選擇加入的應用程式啟用預測返回動畫

Beginning in Android 15, the developer option for predictive back animations has been removed. System animations such as back-to-home, cross-task, and cross-activity now appear for apps that have opted in to the predictive back gesture either entirely or at an activity level. If your app is affected, take the following actions:

  • Ensure that your app has been properly migrated to use the predictive back gesture.
  • Ensure that your fragment transitions work with predictive back navigation.
  • Migrate away from animation and framework transitions and use animator and androidx transitions instead.
  • Migrate away from back stacks that FragmentManager doesn't know about. Use back stacks managed by FragmentManager or by the Navigation component instead.

使用者強制停止應用程式時，小工具會停用

如果使用者在搭載 Android 15 的裝置上強制停止應用程式，系統會暫時停用所有應用程式小工具。小工具會顯示為灰色，使用者無法與其互動。這是因為從 Android 15 開始，系統會在應用程式強制停止時取消所有應用程式的待處理意圖。

系統會在使用者下次啟動應用程式時，重新啟用這些小工具。

詳情請參閱「套件停止狀態的變更」。

媒體投影狀態列晶片會提醒使用者分享螢幕畫面、投放及錄製畫面

Screen projection exploits expose private user data such as financial information because users don't realize their device screen is being shared.

For apps running on devices with Android 15 QPR1 or higher, a status bar chip that is large and prominent alerts users to any in‑progress screen projection. Users can tap the chip to stop their screen from being shared, cast, or recorded. Also, screen projection automatically stops when the device screen is locked.

Status bar chip for screen sharing, casting, and recording.

Check if your app is impacted

By default, your app includes the status bar chip and automatically suspends screen projection when the lock screen activates.

To learn more about how to test your app for these use cases, see Status bar chip and auto stop.

背景網路存取權限制

In Android 15, apps that start a network request outside of a valid process lifecycle receive an exception. Typically, an UnknownHostException or other socket-related IOException. Network requests that happen outside of a valid lifecycle are usually due to apps unknowingly continuing a network request even after the app is no longer active.

To mitigate this exception, ensure your network requests are lifecycle aware and cancelled upon leaving a valid process lifecycle by using lifecycle aware components. If it is important that the network request should happen even when the user leaves the application, consider scheduling the network request using WorkManager or continue a user visible task using Foreground Service.

淘汰項目

每個版本發布時，特定 Android API 可能會過時，或需要重構，才能提供更優質的開發人員體驗或支援新的平台功能。在這種情況下，我們會正式淘汰過時的 API，並引導開發人員改用其他 API。

淘汰表示我們已終止對 API 的官方支援，但開發人員仍可繼續使用。如要進一步瞭解 Android 這個版本中的重大淘汰項目，請參閱淘汰項目頁面。